Role of MRI in the detection of marrow bubbles after musculoskeletal decompression sickness predictive of subsequent dysbaric osteonecrosis

Abstract

Dysbaric osteonecrosis (DON) usually occurs in professional divers or compressed air workers exposed to iterative high ambient pressure, but has also been reported to occur in recreational scuba divers. In certain circumstances, DON can be considered as a late manifestation of a previous musculoskeletal decompression sickness (DCS) or ‘‘the bends’’ (historically, type 1 DCS). However, despite the observed link between the two illnesses, their correlation remains controversial. There is a general consensus that gas bubble formation during decompression is the primary cause of DCS and DON. Most hypotheses focus on an autochthonous bubble mechanism but there is no agreement on the actual site as far as DCS development is concerned, and it is unclear where, or how bubbles form in the bone marrow cavity causing DON. Magnetic resonance imaging (MRI) is a wellestablished technique to diagnose osteonecrotic lesions. However, there are no specific signs on MRI to correlate the dysbaric origin to osteonecrosis, except the patient’s medical history. In this paper, we present two cases of musculoskeletal DCS in recreational scuba divers with DON complications with initial MRI detection of microaeric cavities in the fatty bone marrow, highly consistent with bubble formation. To our knowledge, these MRI findings compatible with bubble-induced